Induced Synthesis of Alkaline Phosphatase by Bile Acids in Rat Liver Cell Culture

Hatoff, David E.; Hardison, W.G.M.

doi:10.1016/s0016-5085(79)80078-5

Cited by 53 publications

(12 citation statements)

References 23 publications

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“…Although the mechanism by which the membrane-bound enzyme induced in the liver is released into the serum as a soluble form has not been clarified in detail, some possible explanations have been presented. With biliary obstruction, for example, the failure of bile flow exposes hepatocytes to increased concentrations of compounds normally excreted into the bile; among such compounds, bile acids seem not only to induce the synthesis of alkaline phosphatase [6] but also to act as a detergent to release the membrane-bound Correspondence to Y. Ikehara, Department of Biochemistry, Fukuoka University School of Medicine, Nanakuma, Jonan-ku, Fukuoka 81 4-01, Japan Abbreviations.…”

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confidence: 99%

Selective preparation and characterization of membranous and soluble forms of alkaline phosphatase from rat tissues

Miki

Tanaka

Ogata

et al. 1986

European Journal of Biochemistry

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We developed a method for selective preparation of two forms of alkaline phosphatase from rat tissues. The enzyme was extracted by n-butanol treatment at pH 5.5 and pH 8.5 as soluble and aggregated (membranous) forms, respectively. The soluble form prepared from liver was found to be identical with the serum enzyme. Complete solubilization of the membrane-bound enzyme without detergents had a great advantage in its purification. Rat hepatoma AH-130 cells enriched in alkaline phosphatase were first used for purification of the livertype enzyme. The hepatoma enzyme, purified by chromatographies on concanavalin-A -Sepharose, Sephacryl S-300 and hydroxyapatite was used for production of antibodies specific for the liver-type isozyme. An immunoaffinity column, prepared with anti-(hepatoma-enzyme) IgG was utilized for the enzyme purification from other tissues including the membranous form. Analyses of amino acid composition of the purified enzymes revealed that all the liver-type enzymes from hepatoma, liver, kidney and serum had the same composition, whereas the intestinal type consisted of the composition distinctly different from that in the liver type. In addition, there was no significant difference in amino acid composition between the soluble and membranous forms, suggesting a possible involvement in the membranous form of a hydrophobic component other than its polypeptide domain. The present method for selective preparation of the soluble and membranous forms of alkaline phosphatase will be useful for a further investigation on the interaction of the enzyme with membranes.

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mentioning

confidence: 99%

Selective preparation and characterization of membranous and soluble forms of alkaline phosphatase from rat tissues

Miki

Tanaka

Ogata

et al. 1986

European Journal of Biochemistry

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“…Hepatocytes respond to conditions of stress or injury induced by cholestasis by the elevated expression of ALP. 5 Although the isoenzyme responsible for the marked increases in activity was not formally identified, it did not have the characteristics of the intestinal isoenzyme in potato starch-fed rats. It presumably represented the liver-biliary isoenzyme that is normally found in hepatocytes and the colonic epithelium.…”

Section: Discussionmentioning

confidence: 99%

“…In hepatocytes, ALP production is induced by potentially injurious agents, such as bile acids, 5 and this forms the basis for the use of serum levels of this enzyme as a test of cholestasis.The major isoenzyme of ALP found in both hepatocytes and the colonic epithelium is the liver-biliary isoenzyme. 6 It is possible that events unrelated to changes in differentiation status per se might also influence ALP activities in the colonic epithelium.…”

Section: Introductionmentioning

confidence: 99%

Relationship of hydrolase activities to epithelial cell turnover in distal colonic mucosa of normal rats

Nov

Fielding

McIntyre

et al. 1999

J of Gastro and Hepatol

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“…Experimental studies have shown that the increased serum activities correlate with increased intracellular activities of the enzyme due to induction within the hepatocytes following an enhanced rate of translation of mRNA (18). The origin of this induction is not known but in primary cultures of hepatocytes, exposed to high concentration of bile acid in the media, there is a marked increase of the activities of ALP in the cells (19).…”

Section: Discussionmentioning

confidence: 99%

“…It has not been completely ruled out, though, that a certain retention of bile might exist and induce the tissue activities of ALP. This possibility has some significance when in vitro data from hepatocytes in primary cell cultures being induced by bile in the tissue culture medium, are taken into consideration (19).…”

Section: Discussionmentioning

confidence: 99%

The source of serum alkaline phosphatases in liver‐tumour‐bearing rats

Hultcrantz

Eriksson

1989

Liver

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ABSTRACT— Patients with hepatic tumours have increased serum activities of alkaline phosphatases. In order to clarify the origin of the increased enzyme activity, two experimental models of rat liver carcinogenesis were studied. In one model, the resistant hepatocyte model, the process was initiated by diethylnitrosamine (DEN, 200 mg/kg), and preneoplastic liver nodules were selected for by 2 weeks of 2‐acetylaminofluorene (2‐AAF, 0.02%) feeding and partial hepatectomy (PH). High activities of serum alkaline phosphatases were found in these rapidly growing nodules harvested at the peak time of nodular mass expansion. In the other model in which nodules were induced with long‐term intermittent feeding of a diet containing 0.05% 2‐AAF and harvested in a late stage with a low increase of nodular liver cell mass, no such increase in serum alkaline phosphatase activity was found. A similar difference was also noted when measuring the activities of the enzyme in the nodular tissue. Thus the first model showed high activities of the enzyme in the nodular tissue, while the second model had similar activities to those of the control animals. The serum levels reflected the nodular enzyme activity in both models. The tissue surrounding the nodules did not show increased enzyme activity. No difference was noted in the serum or tissue activity of transaminases. In both models the liver nodules occupied 30–50% of the liver volume. The experimental models were selected to emphasize the importance of the rate of intrahepatic mass expansion for the levels of serum alkaline phosphatase activities. Our findings indicate that the increase in serum activities of alkaline phosphatase was caused by induction and release of the enzyme in the nodules themselves rather than by tissue compression and a following cholestasis of the surrounding liver tissue.

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Induced Synthesis of Alkaline Phosphatase by Bile Acids in Rat Liver Cell Culture

Cited by 53 publications

References 23 publications

Selective preparation and characterization of membranous and soluble forms of alkaline phosphatase from rat tissues

Selective preparation and characterization of membranous and soluble forms of alkaline phosphatase from rat tissues

Relationship of hydrolase activities to epithelial cell turnover in distal colonic mucosa of normal rats

The source of serum alkaline phosphatases in liver‐tumour‐bearing rats

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